Grinder



R. PRATER July 1, 1930.V

GRINDER Filed March 17, 1927 .......l ---l- JN ,Patentedlfluly l., ,A

RALPH 'BR-Arme, :or CHICAGO, ILLINOIS:

y :Gamesa application meenemen, 192;7. *semi No. 17:55991 L v VMy'inventiofn relatesk particularly to grinders of the type adapted forreducino materials of variouskinds, andisfparticularly adapted for `craclii'ig corn'although notlimited to 5 this use'alone.

Thel mainv object lof the .invention Y resides in the prwisi'onof, a' simple Vand eiiicient grinder of the abo-ve type whicliiis'adapted to Y reduce material toa more or less, uniform size 16 without necessarily producing a considerable percentageofundesired meal orfinely pulver- V ized material, and which requires a compara-y tively small amount 'of power for operation. With this objectinviewmy invention con- 15 sist-s in certain features Aof-novelty in the con-v structiom combination, and arrangement of parte,Y by Which the,l said object and; certain other objects hereinafter appearing areeffected' all as fully described'withreference tol 2@ the accompanyingfdrawing*and more particularl'y pointed. outin'theappendedclaims. lnfothe'said drawing-` `j j Y l Eigureil is av Central vertical longitudinal sectionofial'grinder embodyingA my invention;

Figure 2 is 'a seetiononthe lineQffZzofFigure 1f' "p i Figure isa partiell section on y'the line 3-is0firigursa ,f f f Like characters: offreference indicate. like Y 30 parts'in theseveral views.

. Referring. to thefdrawing, '1 designates va casing the upper portion of which is semi- V circular on ajhorizo'ntal axis and substantially uniform insize longitudinally of said axis. See Figures 1 and 2. The wallsof the casing extend downwardly from said upper portion and legs 2 secured at the lower ends of sai-:l walls'support the .casing in an elevated Ythrough the casing in coaxial relation with the uppercportion thereofyand is ournaled in suitable bearings 4 on the end wallsV of the casing.v A pull'eyf is securedon the shaft 3 on the outside ofthe casing-for rotation ofthe r shaft from a suitable sourceof power through the medium of a belt 6.'

Secured on the shaft 3 within the casing adjacent. the respective ends ofthe enclosure thereof are two disks 7, and mountedon these disks and extending therebetween'in diamet-l pe'sition.' .Ai revoluble` shaft 3 extends yrigca'lly opposite relation with and inparal.-y

lelismw-itlr the shaftare two rods 8. Pivot@ ally-'mounted on the rods 8 between they disks 'Z KYareftw'ofsets ,ofblades or hammers 9A which are maintained in4 spaced. relationv by means ofspacingcollars 10 on the rods, and another diskfll embraces the'shaftl'andthe rods 8 j inteiunediate"thedislrsl 8 to resist bendingof the rods under centrifugal force. The blades l9 lon each rod 8 arev of different lengths and consequently have different radii and are -ar" ranged'.correspondingly and in progression hereinafter described. s y Y T'lie-glower'portion of the casing is opento `corresponding with-their radii for purposes forni bottom discharge opening extending v the entirelengtlr ofsaid progression Aof ,blades, as'Ydesignatedl at 12,' and horizontal wa'llportions 13 arel :formedl on the casing in the horizontal plane ofthe shaft 3k on opposite sides thereof and these wall portions vextend'iffrom thewall of thev upper `portion of the casing inwardly and` havetheir inner edges 14 disposed adjacent to and extending in correspendence with the" periphery of, the pathsy v`ofthe blades V9 effected by rotation of the shaft 3, centrifugalforce maintaining the blades in' radial relation with the shaft durin'gjrotationA thereof at operating: speed. See FiguresfQ` andiS. A uniform sizing'screen 1,5 issecured with thejcasing ina suitable manner andcovers allof thedi'scharge opens ing `12v-and extends lfrom theinner edges le of the wall portionsr lb'elow thesamearoundV the lowery portion of V'the periphery of the' paths ofthe blades 9 equidistantadjacency` 'rhe @ssi-ngi isipfoifiaeu Webmin-iet 015x511! c ing' 16 'atithe, endthereof adjacent the endf'of thepregression of yblades having the smallest f iin operation the sha-ft 3 is driven kkat' asuitablespe'edand' materialto be reduced is fed f into thelcas'ingthroughthe vinlet opening 16,

to stiiikelthe'materiali-ngthe casing-*With forcek s -Ifeduced'isuilicientl'y itl discharges {thescreen-151 Byreason ofthe-difvarying with their radii. As the material is fed into the casing it first encounters the blades of the smallest radii andaccordingly is subjected to the weakest blows, and as the material progresses in the casing away from the inlet end thereof it is subjected to blows of graduall increasing force until it is reduced sufficiently to pass through the screen 15. Thus, it will be observed that the material is subjected to the action of thev blades 9 only until it is sufficiently reduced to pass through the screen, as it may discharge at any point in its passage in the casing away from the inlet opening where it has been sufficiently reduced to pass through the screen and is not subjected to more blows of greater forceA than Vare necessary for reducing it to the desired size. j Thus is thepercentage of undesired meal or finely .pulverized material reduced and the already sufficiently kreduced material discharging directlyout of the cas.- ing does not interfere with the reduction of other material with obvious advantage both as to `efliciency in reduction and power required for loperatlon. j

j By reason of theform of the upper portion of the. casing, which it will be observed is uniform in size longitudinally of the shaft 3 Vand does not conform with the periphery of the paths of the progression of blades 9, space is provided wherein material, which after encountering all of thek blades9 is not Vreduced sufficiently to pass through the screen V15, is passed back toward the inlet opening for additional action by the blades. It will be observed that the wall portions 13 provide shelf surfaces which are particularly advantageous in the reduction of material of comparatively large size, such as ear corn, as they have a tendency to advantageously retard rotation of the material with the blades 9 and to churnvthe material.

While I have herein shown and particularly described 'the preferred embodiment of my invention I do not wish to be limited to the precisedetails of construction shown as i f changes may readily be made without depart- 1. Ina grinder v'ing from the spirit of my invention, but having lthus describedmy invention I claim as new and` desire to secureby Letters Patent the following z-l-Y ,Y

the combination with a casing, ofjayplurality -of coaxially disposed r0- tatory reducing* devices of Adifferent lradii within said casing and arranged in progression corresponding with their radii, said casj -inghaving one portion thereof of substani tially unlform size longitudinally of the axis progression intermediate the said portions of the casing and extending from the Walls of said first mentioned portion inwardly and having their inner edges disposed adjacent to and extending in correspondence with the periphery of the paths of said reducing devices, and a uniform sizing screen coverinflr all of said discharge opening and extending from said inner edges of said wall portions and in said second mentioned portion of the casing around the corresponding portion of the periphery of the paths of said reducing devices in equidistant adj acency therewith.

v 2. In a grinder the combination with a casing, of a horizontal revoluble shaft extending through said casin in central relation therewith, a-plurality `o reducing members of different radii carried by said shaft for rotation therewith Yand arranged in pro ression corresponding With their radii, sai casing having the enclosure of the upper portion thereof of substantially uniform size longitudinallyof said shaft and having' an inlet opening adjacent the end of said progression having the smallest vradius and a bottom discharge opening in the lower'p'ortion thereof extending substantially the entire length of said progression, horizontal wall portions on said casing disposed in the horizontal plane of said shaft on opposite sides thereof, and extending from the wall of said first mentioned portion inwardly and having their inner edges disposed adjacent to and extending in correspondence with the periphery of the paths of said reducing devices, and a uniformsizing screen covering all of said discharge opening and extendin lfrom said inner edges of said wallportions .below the saine around the lower portion of the periphery of the paths of said reducing devices in equidistant adjacency thereto.

In witness whereof I hereunto affix my signature this fourteenth day ofMarch,'1927.

f RALPH'PRATER.

and said reducing devices and having an inlet A Vopening adjacent the'end of said progressionv having the smallest radius and having a discharge opening inthe other portion thereof extending substantially the entirel length of said progression, wall portions on said casing disposed on oppositesides of the path of said 

